June 21, 2015

Walking with Dinosaurs at the Summer Solstice

Led by a white Forest Service pickup, the "auto tour" forms up.

What I think of when I hear "auto tour."

There is something old-fashioned about the phrase “auto tour”—
as in Picketwire Canyonlands Guided Auto Tour — which suggests maybe
a 1920 Studebaker Big Six “touring car” with the top down.
Goggles and dusters absolutely required.

We were instead in M’s faithful 1997 Jeep Wrangler, and I was
shifting in and out of 4wd low range all day long, mostly when
descending steep, rocky, glorified wagon roads into the Puragatory
Canyon.*

Seventeen vehicles full of people who had paid $15 apiece for adults
started out; fifteen made it into the canyon. Flat tires were like a
spreading virus — blame the sharp shale up top or the sharp rocks anyplace?

Friends in Pueblo set this up—we were supposed to have gone in May,
when it would not have been over 100° F as it was on Saturday, but all tours were
canceled due to wet weather. We still had to skirt a few mud bogs, but most of the roads
were dusty. Very dusty. And there was little shade, and if there was, the piñon gnats were waiting.

The centerpiece of the tour is the famous dinosaur trackway, which preserves more than "1300 prints in 100 separate trackways [along] a quarter-mile expanse of bedrock," to quote the brochure. And there are more waiting to be uncovered.

Credit for the discovery goes to a 1936 schoolgirl in the downstream hamlet of Higbee; some paleontologists made quick visits shortly after that — and then scientific interest languished until the 1980s when they were "re-discovered."

Scaled-down dinos play out the tracks' drama

Now there is signage, and a pilgimage to "the dinosaur tracks" has become One of the Things You Do in Colorado.

In the photo, our Forest Service interpreter-guide-wagonmaster has set down Allosaurus and Apatosaurus models — placing them in the tracks made by real things in the muddy shore of a Jurassic lake. At this spot, the carnivorus Allosaurus has stepped directly on the tracks of an apparent family group of large and small Apatosaurus browsers. The presumption is that it was stalking them.

Some smaller dinosaurs,Ornitholestes, also left their tracks. They too walked on their hind legs and weighed maybe 25–35 pounds.

In fact, the different stops are like an experiment in temporal dislocation. While it is 150 million years ago at the trackway, at another stop, it is a few hundred years or a couple of millennia ago. At yet another, a 19th-century family cemetery holds the graves of New Mexican settlers who farmed from the 1860s to the early 1900s, while up the canyon, time has stopped in the 1970s, when the Army condemned thousands of acres to create the Piñon Canyon Maneuver Site. All of this in eight hours of dusty roads!

A juvenile hominin follows adults across the trackway by the Purgatory River. No Allosaurus is chasing him!

Kevin, our guide, held off on the "get out of Purgatory" jokes until it was time to do just that, for which I thank him.

*In Spanish, El rio de las animas perdidas in purgantorio (River of the lost souls in Purgatory); in fur-trapper French, Purgatoire; and in cowboyese, Picketwire. Named for members of a 17th(?) or 18th(?)-century Spanish expedition wiped out by Indians, an expedition that no one seems to be able to date or accurately describe. Nowadays often just called The Purg. But the name is old. M. is dismayed that the Forest Service has given its official blessing to "Picketwire" in its maps and signage on the Comanche National Grasslands.